The effects of fluorine substitution on the 35Cl NQR spectra of fluoroaromatic compounds containing element-chlorine bonds

The ³⁵Cl NQR spectra of pentafluorosubstituted derivatives of benzene C₆F₅X (X = NPCl₃, CONPCl₃, SO₂NPCl₃, NCCl₂, SCl, COCl, SO₂NCl₂, CONCl₂, PCl₂, SO₂Cl) and phosphazocompounds (dimers, [RNPCl₃]₂; R = C₆F₅, C₆H₅, 2,3,5,6-tetrafluoropyridyl) have been recorded and interpreted. On passing from phenyl to pentafluorophenyl derivatives, the ³⁵Cl NQR frequencies increased. The influence of the relative numbers and positions of the fluorine atoms in the benzene ring on the ³⁵Cl NQR frequencies of fluoro-containing benzoyl chlorides has been discussed. The results are explained in terms of charge alteration on chlorine under the influence of the aromatic fluorine atoms. A linear correlation has been found between ³⁵Cl NQR frequencies of pentafluorophenyl derivatives and those of their hydrocarbon analogues. A relationship between elecronegativity of the element and the ionic character of the element-chlorine bond has been revealed. The reactivities of pentafluorophenyl and phenyl derivatives containing element-chlorine bonds have been predicted using the ν_Cl values.     

Study on synthesis of lanthanide chelates of fluorochloroalkyl β-diketones useful as shift reagents

Several lanthanide chelates of the fluorochloroalkyl β-diketones Ln(CF₂ClCOCHCOR)₃ ·nH₂O were prepared (2, Ln=Eu; 2a, R=C(CH₃)₃, n=0; 2b, R=C₆F₅, n=0; 2c, R=CF₂Cl, n=2. 3, Ln=Pr; 3a, R=C (CH₃)₃, n=0; 3b, R=C₆F₅, n=l; 3c, R=CF₂Cl, n=2. 4, Ln=La, R=C₆H₅, n=0) and the NMR shift data of compounds 2 and 3 had been determined using alcohols, ether, ketones and amine as substrates. With alcohol, ether and ketone, compounds 2 induces shifts similar to that induced by Eu (fod)₃. However due to the high solubility of the chelates in non-polar organic solvents such as CHCl₃ and CCl₄ and the absence of ¹H signal from compounds 2b and 2c, their application as a series of new ¹H NMR shift reagents seems promising.     

Perhalophenyl complexes of palladium(II) containing keto-stabilized phosphorus ylides of the type Ph2P(CH2)nPPh2CHC(O)R

From suitable perhalophenyl derivatives of palladium(II), viz.: Pd(C₆F₅)₂-(SC₄H₈)₂, [Pd(μ-X′) (C₆X₅)₂]₂(NBu₄)₂, [Pd(μ-Cl)(C₆X₅)(SC₄H₈)]₂ (X = F, Cl, X′ = Cl, Br), new complexes of various types have been prepared, viz.: trans-Pd(C₆F₅)₂(Y)₂, Pd(C₆X₅)₂(Y), PdCl(C₆X₅)(Y) (X = F, Cl). The neutral ligand Y is a keto-stabilized phosphorus ylide of the type Ph₂P(CH₂)_nPPh₂CHC(O)R (n = 1, R = CH₃, C₆H₅; n = 2, R = C₆H₅) acting in a terminal monodentate P-donor or a bidentate chelate P,C-donor mode. The reaction of PdCl(C₆F₅)(Y) complexes with HCl leads to the corresponding PdCl₂(C₆F₅)(YH) complexes in which the phosphonium cation [YH]⁺ behaves as monodentate P-donor at its phosphinic end.IR and ³¹P NMR spectroscopy were used to decide the coordination mode of the ligands and, in some cases, to reveal the presence of two isomers.     

Reactions of Dicyclopentadienyltitanium(III) compounds with carbon monoxide

Reactions of Cp₂TiR (R = Cl, C₆F₅, C₆H₅, o-CH₃C₆H₄) with CO give two types of products: terminally coordinated adducts, Cp₂Ti(R)CO, and insertion products, Cp₂TiCOR, i.e. acyl compounds. The acyl ligand is η²-coordinated at the titanium atom. The preparations and properties of the compounds are described.     

Strukturen von neuen Bis(pentafluorophenyl)halogenomercuraten [{Hg(C6F5)2}3(μ‐X)]— (X = Cl,Br, I)

Structures of New Bis(pentafluorophenyl)halogeno Mercurates [{Hg(C₆F₅)₂}₃(μ‐X)]^— (X = Cl, Br, I) From the reactions of [PNP]Cl or [PPh₄]Y (Y = Br, I) with Hg(C₆F₅)₂ crystals of the composition [Cat][{Hg(C₆F₅)₂}₃X] (Cat = PNP, X = Cl ( 1 ); Cat = PPh₄, X = Br ( 2 ), I ( 3 )) are formed. 1 crystallizes in the triclinic space group P1¯, 2 and 3 crystallize isotypically in the monoclinic space group C2/c. In the crystals the halide anions are surrounded by three Hg(C₆F₅)₂ molecules. The reaction of [PPh₄]Br with Hg(C₆F₅)₂ under slightly changed conditions gives the compound [PPh₄]₂[{Hg(C₆F₅)₂}₃(μ‐Br)][{Hg(C₆F₅)₂}₂(μ‐Br)] ( 4 ).     

Organomercury compounds XX Reactions of lithium polyfluorobenzenesulphinates with mercuric salts

The lithium polyfluorobenzenesulphinates, Li O₂SR (R = C₆F₅, $\text{p}$-HC₆F₄, $\text{m}$-HC₆F₄, or $\text{o}$-HC₆F₄), and the dilithium tetrafluorobenzenedisulphinates, $\text{p}$- and $\text{o}$-(LiO₂S)₂C₆F₄, have been prepared by reaction of the appropriate polyfluoroaryllithium compounds with sulphur dioxide. All compounds were isolated as hydrates and gave the corresponding $\text{S}$-benzylthiouronium salts on treatment with $\text{S}$-benzylthiouronium chloride. From reactions of the lithium sulphinates with suitable mercuric salts in water, generally at room temperature, the derivatives RHgX (R = C₆F₅, X = Cl, Br, CH₃CO₂, or PhSO₂; R = $\text{p}$-HC₆F₄, X = Cl, Br, or CH₃CO₂; R = $\text{m}$-HC₆F₄, X = Cl or Br; R = $\text{o}$-HC₆F₄, X = Cl), $\text{p}$-(XHg)₂C₆F₄ (X = Cl, Br, or CH₃CO₂), and $\text{o}$-(XHg)₂C₆X₄ (X = Cl or Br) have been prepared. Similarly, the bispolyfluorophenylmercurials R₂Hg (R = C₆F₅, $\text{p}$-HC₆F₄, or $\text{m}$-HC₆F₄) have been prepared from the corresponding lithium sulphinates and either mercuric salts or polyfluorophenylmercuric halides in aqueous $\text{t}$-butanol. A possible mechanism for the sulphur dioxide elimination reactions is discussed.     

Synthetic studies of organodi-π-cyclopentadienyl- titanium (III) derivatives

Two synthetic routes to compounds of the type π-Cp₂Ti^IIIR (R=CH₃, CH₂Si(CH₃)₃, C₆F₅) have been investigated: (a) chemical reduction of π-Cp₂Ti^IV(R)Cl by zinc or aluminum metal in tetrahydrofuran, and (b) conventional organometallic syntheses using organo-lithium or -magnesium reagents and [π-Cp₂Ti^IIICl]₂. The preferred route is via an organolithium reagent, since chemical reduction gives a mixture of products. Green, monomeric complexes (R = CH₂Si(CH₃)₃, C₆F₅) were isolated and characterised. From the reaction of π-Cp₂Ti^IVCl₂ and trimethylsilylmethyllithium in a 1/1 ratio, π-CpTi^IV [CH₂Si(CH₃)₃]₃ was obtained. Unlike π-Cp₂Ti^IIIC₆F₅, π-Cp₂Ti^IIICH₂Si(CH₃)₃ does not form a blue complex with molecular nitrogen.     

Basicity of bisperhalophenyl aurates toward closed-shell metal ions: metallophilicity and additional interactions

The interaction of bisperhalophenyl aurates [AuR₂]^? (R?=?C₆F₅, C₆F₃Cl₂, and C₆Cl₅) with the closed-shell Ag⁺, Cu⁺, and Tl⁺ ions has been studied theoretically and compared with the experimentally known X-ray diffraction crystal structures. Initially, the aurates have been fully optimized at MP2 level of theory in a D _2h symmetry. The analysis of the basicity of the three aurates [AuR₂]^? (R?=?C₆F₅, C₆F₃Cl₂ and C₆Cl₅) against Ag⁺ ions in a C _2v symmetry has been calculated in point-by-point bsse-corrected interaction energy analysis at HF and MP2 levels of theory. Taking into account the experimental observation of additional interactions between the heterometals and C _ipso atoms at the perhalophenyl rings or halogen atoms at the ortho position of the perhalophenyl rings, dinuclear models of the type [AuR₂]^?···Ag⁺ (R?=?C₆Cl₅, and C₆F₅); [AuR₂]^?···Cu⁺ (R?=?C₆F₅, and C₆Cl₅) and [AuR₂]^?···Tl⁺ (R?=?C₆F₅, and C₆Cl₅) with a C _2v , C ₂ , and C _s symmetries have been optimized at DFT-B3LYP level. The interaction energies have been computed through bsse-corrected single point HF and MP2 calculations. The energy stabilization provided and the heterometal preference have been analyzed and compared with the experimental results.     

Pentafluorphenylverbindungen des Phosphors

Pentafluorophenyl Compounds of Phosphorus The preparation of compounds of the type R(C₆F₅)PX (R = CH₃, C₂H₅, t-C₄H₉ and C₆H₅: X = F, Cl, Br and N(C₂H₅)₂) is described. These derivatives are converted to trifluorophosphoranes, R(C₆F₅)PF₃, and phosphinic acid fluorides, R(C₆H₅)P(:O)F. The n.m.r. spectra are discussed.     

The 35Cl NQR spectra and structure of pentafluorophenyltetrachlorophosphorane C6F5PCl4

The low temperature structure of C₆F₅PCl₄ was confirmed by ³⁵Cl NQR measurements as ψ-trigonal bipyramidal, with the C₆F₅ group axial. Discrepancies were found with previously reported data, possible causes of these are discussed.     

Magnitude and origin of the attraction and directionality of the halogen bonds of the complexes of C6F5X and C6H5X (X = I, Br, Cl and F) with pyridine

The geometries and interaction energies of complexes of pyridine with C₆F₅X, C₆H₅X (X=I, Br, Cl, F and H) and R_FI (R_F=CF₃, C₂F₅ and C₃F₇) have been studied by ab initio molecular orbital calculations. The CCSD(T) interaction energies (E_int) for the C₆F₅X–pyridine (X=I, Br, Cl, F and H) complexes at the basis set limit were estimated to be ?5.59, ?4.06, ?2.78, ?0.19 and ?4.37 kcal mol^?1, respectively, whereas the E_int values for the C₆H₅X–pyridine (X=I, Br, Cl and H) complexes were estimated to be ?3.27, ?2.17, ?1.23 and ?1.78 kcal mol^?1, respectively. Electrostatic interactions are the cause of the halogen dependence of the interaction energies and the enhancement of the attraction by the fluorine atoms in C₆F₅X. The values of E_int estimated for the R_FI–pyridine (R_F=CF₃, C₂F₅ and C₃F₇) complexes (?5.14, ?5.38 and ?5.44 kcal mol^?1, respectively) are close to that for the C₆F₅I–pyridine complex. Electrostatic interactions are the major source of the attraction in the strong halogen bond although induction and dispersion interactions also contribute to the attraction. Short‐range (charge‐transfer) interactions do not contribute significantly to the attraction. The magnitude of the directionality of the halogen bond correlates with the magnitude of the attraction. Electrostatic interactions are mainly responsible for the directionality of the halogen bond. The directionality of halogen bonds involving iodine and bromine is high, whereas that of chlorine is low and that of fluorine is negligible. The directionality of the halogen bonds in the C₆F₅I– and C₂F₅I–pyridine complexes is higher than that in the hydrogen bonds in the water dimer and water–formaldehyde complex. The calculations suggest that the C? I and C? Br halogen bonds play an important role in controlling the structures of molecular assemblies, that the C? Cl bonds play a less important role and that C? F bonds have a negligible impact.     

The mass spectra of some pentafluorophenylthio derivatives

Ionic fragmentations induced by electron-impact on compounds of the type C₆F₅SX (X ? H, CH₃, COCH₃, Cl, C₆F₅) and (C₆F₅S)₂, (C₆F₅S)₂Hg, (C₆F₅S)₃As and (C₆F₅SCH₂)₂ have been studied. Principal features of the mass spectra are reported. The [C₆F₅S]⁺ ion (m/e 199) is predominant and its mode of fragmentation has been deduced. The precursor ions for m/e 199 have been examined in (C₆F₅)₂S, (C₆F₅S)₂, (C₆F₅S)₂Hg, (C₆F₅S)₃As and C₆F₅SCl. Ion kinetic energy spectra of (C₆F₅)₂S, (C₆F₅S)₂, (C₆F₅S)₂Hg and C₆F₅SCl have been recorded, and all contain peaks corresponding to the fragmentation of the [C₆F₅S]⁺ ion.     

Polymerization of ethylene with nickel α-diimine catalysts

Several nickel α-diimine compounds of the general formula (ArNC(R) C(R)NAr)NiX₂ (Ar = 2,6-alkyl substituted Ph, R = H or CH₃, X = Br or CH³) were tested in ethylene polymerization after activation with different co-catalysts, such as methylaluminoxane, Al(C₂H₅)₂Cl or other aluminium alkyls, and ionizing reagents like B(C₆F₅)₃, [CPh₃][B(C₆F₅)₄] or HBF₄. The performances of the different catalytic systems were compared with reference to polymer productivity and structure. The degree of branching of the obtained polyethylenes was shown to depend not only on the ligand environment at the Ni centre but also on the type of co-catalyst.     

Polynuclear palladium and gold perhalophenyl derivatives with dppm bridges. Crystal and molecular structure of trans-C6F5Au(μ-dppm)Pd(C6F5)2(μ-dppm)AuC6F5 (dppm = Ph2PCH2PPh2)

Reactions of PdRR′(η¹-dppm)₂ (R = R′= C₆F₅ or C₆Cl₅; R = C₆F₅, R′= Cl; dppm = Ph₂PCH₂PPh₂) with the gold derivatives ClAu(tht), C₆F₅Au(tht), (C₆F₅)₃Au(tht) or O₃ClOAuPPh₃ (tht = tetrahydrothiophen) in appropriate ratios yield the bi- or tri-nuclear complexes PdRR′(dppm)₂AuCl, PdRR′(dppm)₂Au(C₆F₅); PdRR′(dppm)₂Au(C₆F₅)₃; PdRR′(dppmAuCl)₂; PdRR′(dppmAuC₆F₅)₂; PdRR′[dppmAu(C₆F₅)₃]₂, [PdRR′(dppm)₂Au]X (X = ClO₄ or BPh₄); [PPh₃Au(dppm)Pd(C₆F₅)₂(dppm)AuCl]ClO₄ or [PPh₃ Au(dppm)Pd(C₆F₅)₂(dppm)Au(C₆F₅)₃]ClO₄. The structure of trans-Pd(C₆F₅)₂[dppmAu(C₆F₅)]₂ has been determined by X-ray diffraction.     

The direct electrochemical synthesis of anionic organodihalocadmate(II) complexes

The tetra-n-propylammonium salts of RCdX₂^? anions (R = CH₃, C₂H₅, C₄H₉, CF₃, C₆H₅, C₆F₅; X = Cl, Br, I) have been prepared by the electrochemical oxidation of cadmium metal. The element forms the sacrificial anode of a cell in which the solution phase is a methanol/benzene mixture containing (C₃H₇)₄NX and RX. Gram quantities of product were obtained by room temperature electrolysis for ca. 5 h.     

Bis(fluorbenzoyloxy)methylphosphanoxide

Bis(fluorbenzoyloxy)methyl phosphane oxides CH₃P(O)[OC(O)R]₂ [R = C₆H₄2F (1), C₆H₄3F (2), C₆H₄4F (3), C₆H₃2,6F₂ (4), C₆H2,3,5,6F₄ (5)] were prepared by treating silver salts of carboxylic acids AgOC(O)R with CH₃P(O)C?₂ (IR-, ¹H-, ¹⁹?F-and ³¹P{¹H}-NMR-data). The mixed anhydrides 1–5 show unusual thermal stability at room temperature. Stability against hydrolysis decreases with increasing number of fluorine-atoms. The reaction of R′P(O)C?₂ [R′ = CH₃, C₆H₅, (CH₃)₃C] with M^IOC(O)R_F [R_F = CF₃, C₂F₅, C₆F₅; M^I = Ag^I, Na^I T?^I] was investigated.     

Organothallium compounds : XVII. Halogenobis(polyfluorophenyl)thallium(III) complexes

The preparations, stabilities and structures of the complexes R₂TlX and R₂ LTlX (R = C₆F₅, p-HC₆F₄, or o-HC₆F₄; X = Br or Cl; L = Ph₃PO, 2,2′-bipyridyl (bpy) or Ph₃P) have been examined or (R = C₆ F₅) reinvestigated. The derivatives R₂TlX are monomeric in acetone, from which the complex (p-HC₆F₄)₂ Me₂COTIBr has been isolated. In this solvent, the complexes R₂LTlX (L = Ph₃PO, bpy, or Ph₃P) undergo partial dissociation by loss of L. When L = bpy, there is also slight ionization into R₂LTl⁺ and R₂TlX^?₂. The acceptor properties of R₂TlX compounds towards uncharged ligands decrease R = C₆F₅ ? p-HC₆F₄ > o-HC₆F₄ > Ph. Dimeric behaviour is observed for R₂TIX compounds in benzene, whilst R₂LTlX (L = Ph₃PO or bpy) derivatives show slight but significant association. In the solid state, R₂TlX compounds are considered to be polymeric with five coordinate thallium, and R₂LTlX derivatives to be dimeric with five (L = Ph₃PO) or six (L = bpy) coordinate thallium by contrast with four coordinate dimeric and four or five coordinate monomeric structures previously proposed for the respective pentafluorophenyl derivatives. Halogen bridging is unsymmetrical for R = C₆F₅ or p-HC₆F₄, but may be more symmetrical for R = o-HC₆F₄ when L = Ph₃PO or bpy. Reported structural data for the complexes (C₆F₅)LTlX (L = Ph₃AsO, Ph₃P, Ph₃As, or 1,10-phenanthroline; X = Br or Cl) and (C₆F₅)₂TlCl^?₂ are reinterpreted and the proposed structures revised.     

Planar Chiral Organoborane Lewis Acids Derived from Naphthylferrocene

Enantiomerically pure metalated 2‐(1‐naphthyl)ferrocene (NpFc) derivatives NpFcM (M=SnMe₃, HgCl) were prepared and characterized by multinuclear NMR and UV/Vis spectroscopy, cyclic voltammetry, and elemental analysis. Optical rotation measurements were performed and the absolute configuration of the new planar chiral ferrocene species was confirmed by single‐crystal X‐ray diffraction analysis. The mercuriated species NpFcHgCl proved suitable as a reagent for the preparation of the chiral organoborane Lewis acid NpFcBCl₂, which can in turn be converted to other ferrocenylboranes by replacement of Cl with nucleophiles. The highly Lewis acidic perfluoroarylborane derivatives NpFcB(C₆F₅)Cl and NpFcB(C₆F₅)₂ were successfully prepared by treatment with CuC₆F₅. The structures were studied by single‐crystal X‐ray diffraction and variable‐temperature ¹⁹F NMR spectroscopy, which suggested that π stacking of a C₆F₅ group on boron with the adjacent naphthyl group is energetically favorable. UV/Vis absorption spectroscopy and cyclic voltammetry measurements were performed to examine the electronic properties of these novel redox‐active chiral Lewis acids.     

19F nmr spectra of mesomeric carbanions generated from polyfluorodiarylacetonitriles. The electronic effect of perfluoroalkyl groups

¹⁹F NMR spectra of 1,2- dimethoxyethane solutions of Na- and Li- salts of polyfluorinated carbanions [p - RC₆F₄$\text{C}$(CN)C₆F₄R′-p] Na⁺ (Li⁺) and of their neutral precursors p-RC₆F₄CH(CN)C₆F₄R′-p / R  F or CF₃ and R′= CF₃, CF₂CF₃, CF(CF₃)₂ and C(CF₃)₃/ have been studied. The values of changes in the chemical shifts of fluorine atoms in the ring and the side chain are practically the same when going from the precursor to carbanion with the perfluoroalkyl group being varied. This gave grounds to conclude that the electronic effect of the perfluoroalkyl groups is rather similar. The ¹⁹F NMR method has revealed no differences in the predominant mechanism of the negative charge distribution by these groups.     

Reactions of tellurium chloride pentafluoride,TeF5Cl,with nitrogen nucleophiles. Preparation and characterization of the adducts (TeF4)2·NR2Cl,where R = CH3, C2H5

Reactions of TeF₅Cl with the nitrogen nucleophiles LiN=C(CF₃)₂, [(CH₃)₃Si]₂NH, and (CH₃)₃SiNR₂, Where R = CH₃, C₂H₅, result in the reduction of the tellurium to Te(IV) and chlorination of the respective nucleophile. Analogous results are obtained in the reactions of TeF₅Cl with (CH₃)₃SiCN, C₆F₅Li, and C₆F₅SLi. In the case of (CH₃)₃SiNR₂, the new adducts (TeF₄)₂·NR₂Cl are obtained in high yield. These compounds have been identified through their infrared, ¹H, ¹⁹F, and ¹²⁵Te NMR, and mass spectra as well as by elemental analysis.